Local marine scientists have described Australia's west coast as the deadliest shark attack zone in the world
Beaches remained closed on Sunday along Australia's west coast after a fatal shark attack that has reignited debate over whether great whites should remain a protected species.
Surfer Benjamin Linden, 24, was bitten in half in a savage attack on Saturday, the fifth such fatality in the region in less than a year.
He was surfing near Wedge Island, north of Perth, with a friend when he was mauled by the huge shark, said to be up to five metres (16 feet) long.
A man jet-skiing near him said it was a gruesome scene, with "half a torso" all that remained of Linden.
Surfers said they had noticed a large shark in the vicinity in the previous few days and nicknamed it "Brutus" due to its large size.
Local marine scientists have described Australia's west coast as the deadliest shark attack zone in the world and Western Australia Fisheries Minister Norman Moore expressed concern at the trend of fatalities.
"We have allocated some Aus$14 million ($14 million) extra to get a better understanding of the great white sharks and the reasons why the fatalities are occurring," he told reporters.
"I wonder if research might tell us that there are now much greater number of great whites than ever before, and maybe we should look at whether they should remain a protected species.
"This is a very distressing event and to add to the previous four fatalities, it is of great concern to me and to the fisheries department, indeed the government as a whole."
A tagging and tracking programme was introduced last year and has shown the animals, which have no predators other than humans, whales and other sharks, can linger off Australia's west coast for months at a time.
Moore said he was open to "any suggestions from anybody as to where we go to now, because we seriously have got a problem".
After the last fatal attack in March, state premier Colin Barnett ruled out a culling programme, saying it was impossible to protect all people at all times.
"While it's still a rare occurrence, the ocean is the domain of the shark and we go there with a risk always," he said at the time.
Sharks are a common feature of Australian waters but fatal attacks are rare.
Experts say the average number of attacks in Australia -- about 15 a year, with at least one being fatal -- have increased in line with population growth and the popularity of water sports.
Linden's girlfriend Alana Noakes posted a tribute to him on Facebook.
"I'm devastated to let everyone know that my beautiful man... was the surfer who was taken by the shark at Wedge," she said.
"He was the love of my life, my best friend, my rock and my soulmate.
"Let's remember that he was doing something that meant the world to him. Surfing was his soul, his life, his culture and his passion."
Western Australian waters are home to more than 100 species of shark, according to the state fisheries department, ranging in size from the pygmy shark at just 30 centimetres, to the whale shark that grows up to 12 metres.